Site-directed drug delivery systems are greatly needed in several areas of medicine. For example, localized drug delivery is needed in the treatment of local infections, such as in periodontitis, where the systemic administration of antimicrobial agents is ineffective.
The problem after systemic administration usually lies in the low concentration of the antimicrobial agent which can be achieved at the target site. A systemic dose increase may be effective to raise the local concentration, but it also may produce toxicity, microbial resistance and drug incompatibility.
Improved methods are needed for the controlled local delivery of drugs.